The present invention relates to error collection which is one of the functions to enhance reliability, availability and serviceability (RAS) of a sorter system.
A hardware sorter system employing a conventional error collection method such as described in Denshi Tsushin Gakkai Gijutsu Kenkyu Hokokusho (Shingaku Giho, Vol. 86, No. 170) CPSY-26 dated Sept. 26, 1986, is shown in FIGS. 7 and 8.
In FIG. 7, the hardware sorter system includes 18 sort elements 61 or P.sub.i (i=1-18) each of which consists of TTL ICs which are SSI and/or MSI mounted on a single substrate; a pipelined data stream 62 for connecting the sort elements through which data flows continuously in synchronism with a control clock; and local memories 63 or M.sub.i (i=1-18), for the first to 12th stage mounted with each P.sub.i (i=1-n) or in the same substrate for the 13th and following stages separately mounted from P.sub.i (i=13-18) on each counterpart. The memory capacity M.sub.i of each local memory increases with the number of M.sub.i =32 B.times.stages i as a function of 2.sup.i-1 ; e.g., M.sub.1 =32.times.2.degree.=32 B (bytes), M.sub.2 =32 B.times.2=64 B, M.sub.3 =32 B.times.2.sup.2 =128 B, . . . , M.sub.17 =32 B.times.2.sup. 16 =2 MB, M.sub.18 =32 B.times.2.sup.17 =4 MB.
In FIG. 8, the hatched areas on the memory substrate indicate the memory portions. A sorter unit 64 consisting of the sort elements and local memories and a sorter driver 65 constitute a sorter system which consists of 29 substrates. The sorter system includes a control line 66 extending from the sorter driver 65 to each sort element 61 and a memory bus 67 being accessible for an external controller to the dual ports memories M.sub.13 -M.sub.18.
In operation, the sorter system with 18 sort elements in FIG. 7 is able to sort 2.sup.18 or 262,144 (N=2.sup.18) records. Finally, the data of N records long are sequentially inputted via the data way 62 to the first sort element P.sub.1, where the first record is loaded in the local memory M.sub.1. Then, the loaded record and the second record inputted are sorted, and after that a string 2 records long is outputted to the next sort element P.sub.2. Secondly, the third and the fourth records are then sorted at the first sort element, followed by the fifth and sixth records. In this way, all the records are sorted in sets of 2, and some strings of 2 record length are outputted sequentially to the next sort element P.sub.2. In the sort element P.sub.2, the first string which consists of the first and the second record sorted at the first sort element P.sub.1 is loaded in the local memory M.sub.2. The loaded first string and the second string which is composed of the third and the fourth record sorted at the first sort element P.sub.1 are sorted, and a string 4 records long is outputted to the next sort element P.sub.3. In this way, two strings of a double record length are sorted in the sort element P.sub.2, two strings of a quadruple record length are sorted in the sort element P.sub.3, and generally two strings of a 2.sup.i-1 record length are sorted in the sort element P.sub.i along the data way 62. Two strings of a 131,072-record length are sorted in the 18th sort element P.sub.18, and the sorted data of a 262,144 (=N)-record length is provided as a final output.
In the conventional error collection method, when a sort element becomes out of order, the types and characteristics of an error in a report to the upper structure increases with the number of sort element stages because of the pipeline connection of sort elements so that it is difficult to process the error. In addition, it is also difficult to determine the time at which the error is collected. For example, if there is a fault on the data bus between two sort elements, the bus parity check is useless during the collection of irregular fault information. Furthermore, if one of the LSI sort elements becomes out of order, the types and characteristics of an error increases with the number of sort element stages because of the pipeline connection of sort elements so that the process of a report to the upper structure becomes complicated. Moreover, because of the linear connection, pipeline parallel processing, a fault in a sort element disables the subsequent sort elements to perform sorting.